documentclass{article}
usepackage{tikz}
usetikzlibrary{decorations.pathmorphing}
newcommandWasserman{tikz[baseline=-0.8ex]{draw[line width=0.07em,decorate,decoration={coil,segment
length=0.45em,amplitude=0.8ex}] (0,0) -- (2em,0);}}
begin{document}
[ X_1 Wasserman X_2]
end{document}